In the related art, there is an operation data management device monitoring a monitoring target such as a plant (for example, refer to PTL 1). The operation data management device compares management values for determining a state with operation data acquired from a monitoring target so as to evaluate whether or not there is abnormality, and the extent of abnormality, and monitors the acquired operation data in a case where it is determined that there is abnormality. Specifically, the management values are set to three values such as an upper/lower limit value, an alarm threshold, and a stoppage value so that a state region of operation data is divided into four regions such as a normal region, a preliminary warning region, a warning region, and a stoppage region. The management values are boundary values for dividing the region.